The present invention relates generally to chucks for hand, electric or pneumatic power drivers. Electric and pneumatic tool drivers are well known. Although twist drills are the most common tools on such drivers, the tools may also comprise screw drivers, nut drivers, burrs, mounted grinding stones and other cutting or abrading tools. Since the tool shanks may be of varying diameter or of polygonal cross-section, the device is usually provided with a chuck that is adjustable over a relatively wide range. The chuck may be attached to the driver spindle by a threaded or tapered bore. A variety of chucks for both hand and power drivers have been developed in the art. In an oblique jawed chuck, a chuck body includes three passageways disposed approximately 120 degrees apart from each other. The passageways are configured so that their center lines meet at a point along the chuck access that is typically forward of the chuck. The passageways constrain three jaws that are moveable in the passageways to grip a cylindrical or polygonal tool shank displaced approximately along the chuck""s center axis. The chuck includes a nut that rotates about the chuck center and that engages threads on the jaws so that rotation of the nut moves the jaws in either direction within the passageways. The body is attached to the spindle of a driver and is configured so that rotation of the body in one direction with respect to the nut forces the jaws into gripping relationship with the tool shank, while rotation in the opposite direction releases the gripping relationship. The chuck may be operated by a chuck key, or the sleeve may be rotated by hand in a keyless configuration. An example of a keyless chuck is disclosed in U.S. Pat. No. 5,125,673 commonly assigned to the present Assignee and the entire disclosure of which is incorporated by reference herein. Various configurations of keyless chucks are known in the art and are desirable in a variety of applications.
The present invention recognizes and addresses the foregoing considerations, and others, of prior art constructions and methods.
Accordingly, it is an object of the present invention to provide an improved chuck for a tool driver.
This and other objects may be achieved by a chuck for use with a manual or powered driver having a drive shaft. The chuck includes a generally cylindrical body member having a nose section and a tail section. The tail section is configured to mate with the drive shaft of the driver, and the nose section has an axial bore formed therein. A plurality of jaws are disposed radially reciprocally within the body in communication with the bore. Each jaw has a jaw face formed thereon for engagement with the tool. A driver is disposed on the body member and in engagement with the jaws so that rotation and/or axial movement of the driver with respect to the body drives the jaws toward or away from the axial bore, depending on the direction of the rotation and/or axial movement. A first detent is disposed in the body in communication with the jaws. At least one of the jaws defines a catch thereon at a predetermined position on the jaw so that the catch engages the first detent when the jaws are at a predetermined position on the chuck body with respect to the axial bore.
In one embodiment of the present invention, a second detent extends into the axial bore so that a tool shank defining a predetermined cross-sectional distance deflects the second detent radially outward as the tool shank is inserted into the axial bore. The jaw faces engage circumferential gripping surfaces of the tool shank when the jaws are in such predetermined position.
In another preferred embodiment, a chuck for use with a manual of powered driver having a drive shaft includes a generally cylindrical body member having a nose section and a tail section. The tail section is configured to mate with the drive shaft of the driver, and the nose section has an axial bore formed therein. A plurality of jaws are disposed radially reciprocally within the body in communication with the bore. Each of the jaws has a jaw face formed thereon for engagement with the tool. An annular nut is axially movably disposed about the body in driving engagement with the jaws so that axial movement of the nut with respect to the body drives the jaws toward and away from the axial bore, depending on the direction of the axial movement. The nut defines a threaded outer circumferential surface. A generally cylindrical sleeve is rotatably mounted about the body and defines a threaded inner circumferential surface engaging the threaded outer surface of the nut so that relative rotation between the nut and the sleeve moves the nut axially with respect to the body. The nut and the body tail section are rotationally coupled by an axially aligned, with respect to the chuck body, slot defined on one of the nut and the tail section and an axially aligned rib defined on the other of the nut and the tail section and received by the slot.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention.